Download SOLAR SYSTEM DEFINITIONS

SOLAR SYSTEM DEFINITIONS
ROTATION: the spinning of the Earth on its axis; The earth rotates once
every 24 hours; this causes day and night!
REVOLUTION: the path the Earth takes around the sun. The earth
revolves around the sun once every 365 days; this combined with the
earth’s tilt causes seasons!
ORBIT: the path the Earth takes around the sun. The earth orbits the sun
once every 365 days in an elliptical shape!
ELLIPTICAL: the shape of the orbit the earth makes around the sun. This
shape looks like an ellipse, or an oval.
AXIS: The imaginary line that the earth rotates on. It is tilted 23 ½
degrees; because it is tilted we have seasons!
PLANET: a large body in space with a nearly spherical shapes that orbits a
star, such as our sun.
INNER PLANETS: the 4 planets closest to the sun. They are small and
rocky: Mercury, Venus, Earth & Mars
OUTER PLANETS: the 4 planets furthest from the sun. They are large and
made mostly of gas: Jupiter, Saturn, Uranus, Neptune
STAR: a sphere of hot, glowing gases that gives off its own light and is held
together by gravity
NUCLEAR FUSION: when, inside a star’s core, particles of hydrogen join
together to form helium
GALAXY: billions of stars and planets, as well as gas and dust; our galaxy
is the Milky Way!
SUN: our closest star; it appears to be much larger than other stars
because it is so close! It is a medium-sized yellow star and is the center of
our solar system
SUN’S GRAVITY: the force that holds all of the planets in orbit around the
sun
EARTH’S GRAVITY: the force that keeps us on the ground
WEATHERING: the process that breaks down and changes rocks
Chemical Weathering changes the substance that makes up
the rocks
Physical weathering breaks the rocks apart, but does not
change what they are made up of.
EROSION: the moving of weathered rock and soil
This can happen from wind, water or ice!
DEPOSITION: the dropping of materials moved by erosion
*Important questions to practice:
What causes Day and Night on Earth?
What causes seasons on Earth?
What is the order of the planets from the sun?
Why is gravity important to the solar system?
Put these in order, by size, from smallest to largest: sun, moon, earth